This invention relates generally to friction clutches, and has particular reference to a novel torque limiting brake for heavy duty automotive clutches.
Brakes for friction clutches have been developed and used heretofore, the purpose of the brake being to stop the rotation of the driven shaft upon disengagement of the clutch. Without a brake, the driven shaft tends to continue rotating after disengagement due to inertia and this causes transmission damaging gear clash in ensuing gear shifting operations. Clutch brakes of the type referred to are disclosed in U.S. Pat. Nos. 2,863,537 and 3,179,217, granted Dec. 9, 1958 and Apr. 20, 1965 respectively to R. S. Root and assigned to the assignee of the present invention.
While clutch brakes minimize damage and noise during gear shifting in motor vehicles, it has been found that the brake itself can become damaged by the application of excessive braking pressure. Thus, excessive torsional loads on the tangs that key the brake to the driven shaft can ultimately cause the tangs to shear. To solve this problem, torque limiting clutch brakes have been developed, such a brake being disclosed in U.S. Pat. No. 3,763,977, granted Oct. 9, 1973 to W. H. Sink. In the Sink brake, which is the closest prior art known to the applicants, pre-loaded Belleville washers are located between an outer friction section and inner brake section and these allow the inner section to slip relative to the outer section when excessive braking pressure is applied.
The applicant herein is one of the applicants in an earlier filed copending application Ser. No. 612,374, filed Sept. 11, 1975, that is directed to a different modification of the torque limiting clutch brake disclosed in the present application.